An increasing proportion of electronic devices used both in consumer and work contexts incorporate cameras which face the user. Such devices include personal computers and laptops, tablets, smartphones, set-top boxes, point of sale systems and physical access control systems. In general, these cameras are intended for use with visual communication services—such as Skype video person-to-person calls—or to enable the user to take photographs and videos of themselves to capture a moment and perhaps to share. For these uses, it is highly desirable for users to be able to see their own image as it is being captured and/or transmitted. Reasons for doing so may include the ability to ensure that a person's facial presentation is attractive enough to share, or that the detail shown in the image is good enough for the purpose intended. In such cases, the user will normally be careful to position the camera at a distance and at an angle that will convey a good impression of their face and which is pleasing to their own eye.
There exists another class of uses for the front camera of a device where it is unimportant or even disruptive to let the user adjust the relative position of face and camera to achieve the most attractive visual result. In these uses the image or video of the user captured by the camera is normally not seen by the user, nor by anyone known to him. Here the important consideration may instead be that the face is close to the camera, or oriented at a particular angle or positioned in a particular position or positions relative to the camera. Sometimes the speed and nature of transaction does not allow for careful aesthetic optimization of the user's pose. There exists a need to provide rapid visual feedback to a user to enable suitable positioning of the face for this class of uses of the front camera of a device.